Furuno CSH-83, CSH-84 manual Fish Schools, Sea surface fish

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Fish Schools

A fish school appears as a mass of echoes on the screen. The color of the mass shows the density of fish schools on the sonar beam. To find distribution and center point of a fish school, try several different tilt angles.

(A)Sea surface fish

Tilt angle: -5° to 10°

Fish school

Sea surface reflections

(B)Midwater, bottom fish Tilt angle: 30° or more

Fish echo which appears before seabed can be detected.

Seabed

Tilt angle: -0° to 20°

Fish echo which appears together with or after seabed can be detected.

Fish school

Seabed echo not displayed because of narrow tilt angle. Sea surface reflections are present.

Fish school

Large midwater fish school is present.

Seabed

When the tilt angle is shallow, the reflection echo from seabed is weak and the fish echo which appears from bottom

is easy to find.

Figure 11-2 Fish schools

11-2

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Contents Color Scanning Sonar 00080806600 Safety Instructions Do not use the equipment for other than its intended purpose Table of Contents PORT/STARBOARD, Horizontal Slice Displays Self Tests This page is intentionally left blank Features ForewordWord to CSH-83/84 Owners System Configuration Standard OptionControl Layout on Display Unit and Remote Control Box Control DescriptionMain Panel Main panel control descriptionControl Function Sub Panel ENDSub Panel 2 data setting window Signal AGCProcess 2AGCAlarm SonarUP/TM SonrbeamRemote Control Box + +Turning the Power On/Off Adjusting Screen Brilliance, Control Panel BacklightingOperational Overview Lowering the TransducerSelecting a Display Mode Display mode descriptionSetting the Tilt Angle Selecting a Display RangeSeabed echo and tilt angle How to discriminate fish echoes from the seabed Points to considerTilt angle for surface fish Tilt angle and sea surface reflectionsSuitable tilt angle Tilt angle and beam coverageAdjusting the Gain Measuring Range and Bearing to a TargetPage Fine Tuning the Picture How to adjust TVGEliminating Unwanted Feeble Echoes Page AGC data setting window SIGNAL, Signal Pulselength data setting window TVGTX,PL2AGC data setting window SIGNAL, Signal Process Suppressing Seabed TailData setting window TVGTX, Output Rejecting Sonar Interference and NoiseIdentifying noise source Changing Tx cycle data setting window Tvgtx CycleAdjusting Beamwidth Setting Noise limiter data setting window SignalMarks, Data and Display Mode Normal display modeMarks and Data Normal display mode w/text Echo sounder combination displayPermanently Displayed Marks and Data History displayErasable Marks and Data Mark/Data DescriptionBearing marker Mark Description Range R Auto Tilt Auto Scan Gain Brill TVG TVG DIM Page Menu Overview User Menu OperationMenu screen location and display mode User Menu Hist DSP/GRPHUser Menu Description Current VEC Save PictureSystem Menu Description FAR TVGTM DSP Target LockBRG Readout Mark SizeMenu Description Data SET Menu Description Color CurveChange Color NET Shoot PlanNET Sonde NET Plot CorrInit SET/TEST Menu Description Defaults Echo TestNET REC Others Event KEYFunction Keys Programming the Function KeysFunction Key Fine Tuning Replaying a Function KeySaving Function Key Settings to a Memory Card Replaying Function Key Settings from a Memory CardThis page is intentionally left blank How to find fish school center Advanced Level OperationFinding Fish School Center Tracking a Fish School target lock Tracking a fish schoolChoosing target lock mode Target lock mark appearanceErasing target lock mark Tracking target lock mark Target lock and tilt angleSetting target lock conditions System Menu Target LockDescription of target lock items Detecting Fish Schools Aurally Fish Alarm How to set the fish alarm zoneHow to relocate fish schools Relocating Fish School for Easy ObservationComparing of Fish School Concentration Estimate marks and their dataHow to measure fish speed Measuring Fish School SpeedEvent Mark 10 Event marksEntering an event mark Erasing an event markTrue Motion Display 12 True motion displayPlotting Net Location Mark 13 Net location markObserving Net Behavior 14 Net behaviorTarget Slice Display No. Display Information ApplicationsThis page is intentionally left blank PORT/STARBOARD, Horizontal Slice Displays Port/Starboard displayHorizontal slice display Horizontal slice displayMemory Card Operations Initializing Memory CardsSaving the Picture Transferring Echo Data from Internal Memory to Memory CardNet shooting data contents Saving Net Shooting DataHow net shooting data is saved Transferring net shooting data to memory cardDeleting Memory Card Contents Replaying Saved DataTurning marks on/off through the data setting window Turning MARKS, Data ON/OFFTurning marks on/off through the user menu 10-2 Interpreting the Display Seabed EchoesFish Schools Sea surface fishSea Surface Reflections WakeFalse Echo by Sidelobe Noise and InterferenceOvervoltage Warning Unretracted Transducer WarningHow to manually raise the transducer Self Tests Opening the Self Test MenuSelf Test Description Single testContinuous test Panel test Color testGray test SIO testInterface Unit CS-120A Self Test Interface unit CS-120A, cover opened13-6 Input Data Selection Selection of Data at Interface Unit CS-120ASetting Distances Between Net Sonde Transmitters How to set net sonde transmitter distancesMaintenance Display Unit MaintenanceHull Unit Maintenance Zinc block near the transducer must be replaced yearlyMenu Tree User MenuData SET Menu Init SET/TEST Menu System Menu Previous Page Specifications SP-1Display SP-2Hull Unit SP-3SP-4 Index 11-2IN-2